Fuse construction



Dec. 13, 1949 H; v. DRYER FUSE CONSTRUCTION Filed Feb. 26, 1948 I N V ENTOR. .Z ewz-y y 9/76?" war/2e;

Patented Dec. 13, 1949 FUSE CONSTRUCTION Henry V. Dryer, Milwaukee,Wis., assignor to Line Material. Company, Milwaukee, Wis acorporati'onof Delaware Application February 26, 1948,. Serial No.11,132

3 Claims. 1

This invention relates to fuse constructions.

Objects of this: invention are. to provide a cartridge type of fuseconstruction in which an outer opaque cylinder is provided and isequipped with transparent means arranged to give a view of theinternally positioned fuse link to ascertain the condition of the fuselink, and in which the. transparent means includes a part, atleast, ofclear acrylic plastic such as Lucite, and in which this plastic materialis located closely adjacent the fuse link and constitutes a discolorablemember which will indicate when the fuse has blown so that the cartridgemay be discarded and a new cartridge substituted.

A further object for one form of the invention is to provide an opaque.outer casing, with a transparent plug screwed therein and formed of aclear acrylic plastic as described hereinabove with the inner end of theplug arranged in close proximity to an intermediate portion of the fuselink and to provide means for holding the intermediate portion of thefuse link in such close proximity to the transparent plastic plug.

Further objects are to provide a cartridge type fuse constructionemploying the plastic transparent indicating member hereinabovedescribed in which the cartridge is closed at both ends and is providedwith are extinguishing material located adjacent the plastic member andwith granular material on opposite sides of the are extinguishingmaterial to provide a cooling and expansion chamber or surface for thegases, the arc extinguishing material being designed to give ofi watervapor and chill the arc and aid in the extinguishing thereof.

An embodiment of the invention is shown in the accompanying drawings, inwhich- Figure l is a longitudinal view through a cartridge type of fuseillustrating one form of the invention.

Figure 2 is a sectional view on the line 22 of Figure 1.

Referring to Figures 1 and 2 it will be seen that the fuse constructioncomprises a cylinder or casing I of fiber or other suitable opaqueinsulating material such, for example, as Bakelite. The tube or casing Iis threaded at opposite ends and is provided With end terminal caps 2and 3. A ceramic rod l preferably of ribbed formation is positionedcentrally of the casing l and is supported at opposite ends by means ofsuitably slotted fittings 5 and 6 of brass or other suitable metal. Thefitting 5 is formed as a unitary structure with the metal disk I whichis spaced from the end of the casing I by means of a gasket 8 and whichbears against the terminal cap 2. The fitting 6. is provided with anextension or rod 9 which projects through an apertured, brass plug It)and is locked thereto by means of a set screw Ii. The set. screw is.reached through a hole i2 formed in the casing or tube l. A yieldinggasket I3. is positioned between a metal washer I4 and the.' plug 13,and the rod 9 projects through an aperture formed in the terminal cap3'. Preferably solder IE is used to close the hole It in the terminalcap 3 after the rod 9 has been inserted.

A fuse wire ll is wrapped about the ceramic rod 4 and has opposite endssecured in any suitable manner, not shown, to the fittings 5 and E. Thefiber casing I is provided with a threaded aperture it into which isscrewed a transparent plug N5 of a clear acrylic plastic material, suchfor example as that commonly known as Lucite. This plug i9 is providedwith a transverse slot 29 so that a screwdriver may be used to positionit. It is equipped with an inwardly projecting extension 2! which bearsagainst the rod 4 and is in close proximity to the central portion ofthe fuse link IT. The rod 4 is preferably notched as indicated at 22 soas to definitely position a portion of the fuse link immediatelyadjacent the inner end of the extension 2i of the plastic plug I9.

The end portions of the casing l are filled with sand 23 and a centralportion is filled with bauxite 24. The bauxite is preferably powderedand the sand is preferably a fine grained, cutting sand. When the fuselink ruptures, it has been found that the rupturing of the fuse linkalmost always occurs centrally thereof. It has been found also that whenthe acrylic plastic plug is subjected to the action of the arc, that itis discolored and such discoloration is easily perceptible from theoutside of the device since the plug I9, 21 is clear and transparent. Inthis way the condition of the fuse link can always be observed fromtheoutside of the opaque casing i.

It has also been found that when the fuse link is ruptured, the sand 23provides expansion chambers and a very extensive condensing surface forthe gases. Also it has been found that the bauxite liberates a quantityof water vapor which assists in chilling the sand and extinguishing thearc. Consequently, the pressure within the closed cartridge type fusedoes not rise to a dangerous extent, even on heavy overloads.

It will be seen that a simple type of cartridge type fuse constructionhas been provided by this invention which is eminently practical andwhich, although the casing is formed of opaque material,

nevertheless is provided with discolorable transparent means whichallows for external inspection with consequent determination of thecondition of the fuse link.

It is intended that whenever one of these fuse devices blows, that itshall be removed and a new cartridge fuse substituted therefor.

Although this invention has been described in considerable detail, it isto be understood that such description is intended as illustrativerather than limiting, as the invention may be variously embodied and isto be interpreted as claimed.

I claim: a

1. A cartridge type fuse construction comprising a tubular outer casingof opaque material having an opening intermediate its ends, terminalsadjacent opposite ends of said outer casing, a ceramic supportingelement located within said outer casing, a fuse link wrapped about saidceramic supporting element, a transparent plug screwed into said openingand a clear acrylic plastic element located adjacent said plug and heldby said plug in close proximity to said fuse link.

2. A cartridge type fuse construction comprising a tubular outer casingof opaque material having an opening intermediate its ends, terminalsadjacent opposite ends of said outer casing, a ceramic supportingelement located within said outer casing, a fuse link wrapped about saidceramic supporting element, a transparent plug screwed into saidopening, and a clear acrylic plastic element located adjacent said plugand held by said plug in close proximity to said fuse link, said ceramicsupporting element having a notch opposite said plastic element arrangedto position a part of said fuse link in immediate proximity to saidplastic element.

3. A cartridge type fuse construction comprising a tubular outer casingof opaque material having an opening intermediate its ends, terminalsadjacent opposite ends of said outer casing, a ceramic supportingelement located within said outer casing, a fuse link wrapped about saidceramic supporting element, a transparent plug screwed into saidopening, a clear acrylic plastic element located adjacent said plug andheld by said plug in close proximity to said fuse link, said ceramicsupporting element having a notch opposite said plastic element arrangedto position a part of said fuse link in immediate proximity to saidplastic element, powdered bauxite located adjacent the sides of saidplastic element and within said casing and surrounding said ceramicsupporting element, and sand within said casing located on oppositesides of said bauxite and surrounding said ceramic element.

HENRY V. DRYER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 636,379 Erikson Nov. 7, 1899856,292 Phelps June 11, 1907 948,296 Schattner Feb. 1, 1910 1,033,754Buchanan July 23, 1912 1,097,964 Banks May 26, 1914 1,140,953 Cole May25, 1915 1,917,407 Tucker July 11, 1933 2,253,719 McMahon Aug. 26, 19412,442,216 Skeats May 25, 1948

